Pulse-echo acoustic ranging systems, also known as time-of-flight ranging systems, are commonly used in level measurement applications. Pulse-echo acoustic ranging systems determine the distance or range to a reflector (i.e. reflective surface) by measuring how long after transmission of a burst of energy pulses the echoes or reflected pulses are received. Ultrasonic pulse-echo ranging systems utilize ultrasonic pulses.
To provide accurate level measurements, the reflected or echo pulses need to be precisely detected and processed. Since the amplitude of the echo pulses can vary, the threshold point on the pulse becomes critical for determining accurate timing information. In ultrasonic based level measurement or echo ranging systems, accuracy of the level measurements has been found to decrease significantly with increasing ranging distances.
Accordingly, there remains a need for improvements in the accuracy of ultrasonic based level measurement and echo ranging systems.